Sanjay Singh, M.D.

The Gut-Brain Connection

A new area of scientific study that holds great promise involves the connection between the gastrointestinal tract and brain function and disease.

This budding area of research focuses on the trillions of “good” bacteria and other microorganisms in our bodies (probiotics), particularly in the intestines, or gut.

Probiotics have been, up until recently, primarily touted by companies selling nutritional supplements and food products. But there has been a shift in interest and research funding as studies have shown that some disorders or diseases could possibly be improved by adjusting the gut microbiome, which is the “community” or ecosystem of microorganisms such as bacteria, fungi and viruses that live in each person’s intestinal tract.

“The impact of altering gut microbiome on various neurobehavioral disorders is particularly exciting,” says Sanjay Singh, M.D., chairman of the Department of Neurology in the School of Medicine, “because this would allow for the possibility of treating diseases that have no treatments at this time, including autism.”

Singh cites the work of Sarkis Mazmanian, Ph.D., a microbiologist at the California Institute of Technology, a pioneer in the study of beneficial microbes. He says one of Mazmanian’s studies showed that mice with some features of autism had much lower levels of a common gut bacterium, Bacteroides fragilis, than healthy mice did. Feeding B. fragilis to the autistic-like mice reversed their symptoms.

Other studies are looking at interactions between gut bacteria and the nervous system, possibly one day affecting such conditions as anxiety, depression, attention deficit hyperactivity disorder (ADHD) and others.

Singh says one study showed that a radical change in diet can quickly shift the microbial makeup of the gut in humans. The hope is that perhaps by adjusting diet, people could shape their gut microbiome to promote health. But he says research is not yet to the point of saying which diet is best for that.